1. Field of the Invention
The present invention relates to an image display device, an image display method, a program, and a projection system for drawing an image in accordance with an operation of an operator, on a display screen.
2. Description of the Related Art
When an image is projected on a screen and supplementary light is further projected on this screen, a technique for detecting the position of the supplementary light emitted from a laser pointer, etc. is used in order to make a change to the point which corresponds to the position of the image where the supplementary light is projected. Japanese Patent No. 2622620 discloses such a technique.
However, according to the technique of Japanese Patent No. 2622620, when taking an image of the supplementary light (spot) projected on the screen in order to detect the position of the supplementary light, an image pickup device for taking an image must face its light receiving surface straight toward the screen. Otherwise, it is impossible to detect the position of the supplementary light appropriately.
Accordingly, the position where the image pickup device is to be placed is restricted, and the position where the operator of the laser pointer, etc. stands, is also restricted. Thus, the operator experiences the difficulty in operating the laser pointer, etc. Further, it is difficult to set the image pickup device in the right position. Especially, in a case where the optical system of the image pickup device causes aberration, it is extremely difficult to determine the right position. Furthermore, if the positional relation between the image pickup device and the screen is fixed where the image pickup device is set in the right position, it is impossible to change the position of the image pickup device. Thus, the image pickup device cannot be used for other purposes.